Aldol and claisen condensations with 1-(3,4-dichlorophenyl)-2-pyrrolidinone

1-(3,4-Dichlorophenyl)-2-pyrrolidinone (I) has been condensed at the 3-position with a series of aldehydes, ketones and esters.     

Chemistry of 1,6-diazaphenalene. Reaction with alkylating and acylating agents

A study of the reactivity of 1,6-diazaphenalene ( 1 ) toward alkylating and acylating agents has been carried out in order to investigate the chemistry of this new heterocycle. Attempts to alkylate 1 were successfully completed by stirring the lithium stabilized anion of 1 with either methyl iodide or benzyl bromide to provide N-alkyldiazaphenalenes 4 and 5, respectively, whereas, experiments performed to alkylate 1 under conditions employed for alkylation of imidazole were unsuccessful. Studies directed toward acylation of 1 did not lead, in general, to isolable acyldiazaphenalenes; however, in one specific case successful acylation of 2-chloro-9-methoxy-1,6-diazaphenalene ( 10 ) did provide a characterisable amide ( 14 ). Where possible the chemistry of 1,6-diazaphenalene has been compared to that reported for imidazole.     

Atom transfer cyclization catalyzed by InCl3 via halogen activation

[reaction: see text] Indium trichloride was found to be an efficient catalyst for the cyclization of allylic halides and alkynes with atom transfer in methylene chloride. Mechanistic evidence supports a cationic reaction pathway with Lewis acid activation of the allylic halogen. Concomitant nucleophilic attack by the alkyne and trapping with halide led to atom transfer cyclization products. Depending on alkyne substitution, a bromine atom was transferred from the substrate or a chlorine atom was transferred from the solvent.     

First example of a di-cadmium tris-phthalocyanine triple-decker sandwich complex

An unprecedented M(II)2Pc3 (M = Cd) triple-decker sandwich complex has been synthesized and characterised by single crystal X-ray crystallography; cyclic voltammetry shows an unusually large range of redox states and EPR spectroscopy indicates that the material exists in at least two redox states, one having spin (1/2).     

Measuring Lineup Difficulty By Matching Distance Metrics With Subject Choices in Crowd-Sourced Data

Graphics play a crucial role in statistical analysis and data mining. Being able to quantify structure in data that is visible in plots, and how people read the structure from plots is an ongoing challenge. The lineup protocol provides a formal framework for data plots, making inference possible. The data plot is treated like a test statistic, and lineup protocol acts like a comparison with the sampling distribution of the nulls. This article describes metrics for describing structure in data plots and evaluates them in relation to the choices that human readers made during several large Amazon Turk studies using lineups. The metrics that were more specific to the plot types tended to better match subject choices, than generic metrics. The process that we followed to evaluate metrics will be useful for general development of numerically measuring structure in plots, and also in future experiments on lineups for choosing blocks of pictures. Supplementary materials for this article are available online.     

Glaciers melt as mountains warm: a graphical case study

For the 2006 ASA Data Exposition we created graphics that, in the legacy of John Tukey, tried to “force the unexpected upon us” (Tukey in Proceedings of the 18th conference on design of experiments in Army research and development I, Washington, 1972). The data were geographic and meteorological measurements taken every month for 6 years on a coarse 24 by 24 grid covering Central America. Using conventional static graphics and some less conventional interactive graphics, we were able to find expected features in the data, such as seasonal patterns, spatial correlations, and El Niño events, as well as some more surprising results, several of which were corroborated by stories in the news.     

New CP-violation and preferred-frame tests with polarized electrons

We used a torsion pendulum containing approximately 9 x 10(22) polarized electrons to search for CP-violating interactions between the pendulum's electrons and unpolarized matter in the laboratory's surroundings or the Sun, and to test for preferred-frame effects that would precess the electrons about a direction fixed in inertial space. We find, /g(P)(e)g(S)(N)//(Planck's constant x c) < 1.7 x 10(-36), and /g(A)(e)g(V)(N)//(Planck's constant x c) < 4.8 x 10(-56) for lambda > 1 AU. Our preferred-frame constraints, interpreted in the Kostelecky framework, set an upper limit on the parameter /b(e)/ 相似文献   

Context-dependent performance standards in DEA

Data envelopment analysis (DEA) is a mathematical approach to measuring the relative efficiency of peer decision making units (DMUs). It is particularly useful where no a priori information on the tradeoffs or relations among various performance measures is available. However, it is very desirable if “evaluation standards,” when they can be established, be incorporated into DEA performance evaluation. This is especially important when service operations are under investigation, because service standards are generally difficult to establish. The approaches that have been developed to incorporate evaluation standards into DEA, as reported in the literature, have tended to be rather indirect, focusing primarily on the multipliers in DEA models. This paper introduces a new way of building performance standards directly into the DEA structure when context-dependent activity matrixes exist for different classes of DMUs. For example, two sets of branches, whose transaction times are known to be different from each other, usually have two different activity matrixes. We develop a procedure so that a set of standard DMUs can be generated and incorporated directly into the DEA analysis. The proposed approach is applied to a sample of 100 branches of a major Canadian bank where different sets of time standards exist for three distinct groups of branches.     

Ultrafast nanoporous silica formation driven by femtosecond laser irradiation

A type of glass modifications occurring after femto‐second laser irradiation gives rise to strong (10⁻²) from birefringence. This form birefringence is thought to be related to index nanostructure (called nanogratings). Analyzing induced tracks in fused silica using scanning electron microscopy (SEM) with nm resolution shows that nanostructures are porous nanoplanes with an average index lower than typical silica (Δn ∼ –0.20). Their origin is explained as arising from fast decomposition of the glass under localized, high‐intensity femtosecond laser radiation where strong nonlinear, multiphoton‐induced photoionization leads to plasma generation. Mechanistic details include Coulombic explosions characteristic of strong photoionization and the production of self‐trapped exciton (STE). Rapid relaxation of these STE prevents recombination and dissociated atomic oxygen instead recombines with each other to form molecular oxygen pointed out using Raman microscopy. Some of it is dissolved in the condensed glass whilst the rest is trapped within nanovoids. A chemical recombination can only occur at 1200 °C for many hours. This explains the thermal stability of such a nanostructure. Precise laser translation and control of these birefringent nanoporous structures allo arbitrarily tuning and positioning within the glass, an important tool for controlling optical properties for photonic applications, catalysts, molecular sieves, composites and more.     

Network DEA pitfalls: Divisional efficiency and frontier projection under general network structures

Data envelopment analysis (DEA) is a method for measuring the efficiency of peer decision making units (DMUs). Recently network DEA models been developed to examine the efficiency of DMUs with internal structures. The internal network structures range from a simple two-stage process to a complex system where multiple divisions are linked together with intermediate measures. In general, there are two types of network DEA models. One is developed under the standard multiplier DEA models based upon the DEA ratio efficiency, and the other under the envelopment DEA models based upon production possibility sets. While the multiplier and envelopment DEA models are dual models and equivalent under the standard DEA, such is not necessarily true for the two types of network DEA models. Pitfalls in network DEA are discussed with respect to the determination of divisional efficiency, frontier type, and projections. We point out that the envelopment-based network DEA model should be used for determining the frontier projection for inefficient DMUs while the multiplier-based network DEA model should be used for determining the divisional efficiency. Finally, we demonstrate that under general network structures, the multiplier and envelopment network DEA models are two different approaches. The divisional efficiency obtained from the multiplier network DEA model can be infeasible in the envelopment network DEA model. This indicates that these two types of network DEA models use different concepts of efficiency. We further demonstrate that the envelopment model’s divisional efficiency may actually be the overall efficiency.